Neoadjuvant therapy does not affect lymph node ratio in rectal cancer.

AIMS: Recently, lymph-node ratio (LNR) has emerged as a prognostic tool in staging rectal cancer. Studies to date have demonstrated threshold values above and below which survival is differentially altered. Neoadjuvant therapy significantly reduces the number of lymph node retrieved. The aim of the present study was to determine the effect of neoadjuvant therapy on LNR and its prognostic properties. METHODS: Consecutive patients who underwent curative rectal cancer resections in a single institution from 2007 to 2010 were reviewed. LNR was stratified into five subgroups of 0, 0.01-0.17, 0.18-0.41, 0.42-0.69 and 0.7-1.0 based on a previous study. The effect of neoadjuvant therapy on lymph node retrieval, LNR, locoregional (LR) and systemic recurrence (SR), disease-free (DFS) and overall survival (OS) was compared between patients who did (Neoadjuvant) and did not (Surgery Alone) receive neoadjuvant therapy. RESULTS: Neoadjuvant and Surgery Alone groups were comparable in gender, age and tumour stage. The number of lymph nodes retrieved were significantly lower in the Neoadjuvant group (p < 0.01). However, LNR remained similar in both groups (p = 0.36). There was no statistical difference in the DFS and OS between the Neoadjuvant and Surgery Alone groups at the various LNR cut off values in patients with AJCC Stage 3 tumours. CONCLUSIONS: LNR ratio remains unaltered despite reduced lymph node retrieval after neoadjuvant therapy in rectal cancer. LNR may therefore be a more reliable prognostic indicator in this subgroup of patients.

High pressure pulsatile lavage irrigation of intraarticular fractures: effects on fracture healing.

OBJECTIVES: To evaluate the effects of pulsatile lavage and bulb syringe irrigation on fracture healing in vivo. DESIGN: Randomized prospective trial in an animal model. SETTING: Medical school orthopaedic department. SUBJECTS: Thirty New Zealand white rabbits. INTERVENTION: The control group (C) underwent osteotomy of the medial femoral condyle, stabilization, and closure. The bulb syringe and pulsatile lavage groups underwent the same procedure as group C, with the addition of irrigation with one liter of normal saline via a bulb syringe (B) or a pulsatile lavage system (P). Animals were administered two fluorescent bone stains: xylenol orange at the time of operation, and calcein green one week postoperatively. Animals were euthanized two weeks postoperatively and femurs were retrieved for histological analysis. MAIN OUTCOME MEASURES: Union was determined by examination of microradiographs under light microscopy. The viability of bone along the fracture site was determined by evaluation of xylenol orange and calcein green staining under fluorescent microscopy. The density of new bone formed in the osteotomy site was assessed by computerized digitization of standardized regions of the proximal and distal osteotomy. RESULTS: Xylenol orange bands were present a mean of 66 +/- 8 percent (mean +/- standard error of the mean), 65 +/- 6 percent, and 44 +/- 5 percent of the distance along the osteotomy in groups C, B, and P, respectively (p < 0.001). Calcein green bands were present throughout the osteotomy site in all specimens. Calcified new bone was present in 62 +/- 4 percent, 58 +/- 7 percent, and 41 +/- 9 percent of the area measured in groups C, B, and P, respectively (p = 0.07). Twenty percent of the osteotomies in groups C and B did not unite, compared with 30 percent in group P (p > 0.5). CONCLUSIONS: Pulsatile lavage irrigation of fresh intraarticular fractures in rabbits has a detrimental effect on early new bone formation; this effect, however, is no longer apparent two weeks following irrigation. While this study evaluated the effects of pulsatile lavage irrigation in noncontaminated fractures without extensive soft tissue injury, the detrimental effects observed on early new bone formation may translate to an increased risk of nonunion in the setting of a contaminated open fracture with extensive soft tissue injury. Based on the results of this investigation, the selective use of pulsatile lavage irrigation appears warranted. In the absence of gross wound contamination, irrigation with a bulb syringe appears less likely to impair fracture healing than does pulsatile lavage irrigation. Expansion of the model used in this study to include bacterial contamination and soft tissue crushing may further elucidate the effects of pulsatile lavage irrigation on fracture healing.

Aspiration of the knee joint before revision arthroplasty.

Sixty-four operative procedures were performed on 55 patients with knee arthroplasties for pain, loosening, instability, or suspicion of infection. Forty-three knees had a preoperative aspiration. In 19 knees, the aspiration showed growth on solid media, and in 18 of these knees the diagnosis of infection was confirmed by the intraoperative cultures. In 1 knee with an infected total knee replacement, the patient was receiving an intravenous antibiotic at the time of arthroscopic irrigation and debridement and the cultures showed no growth. In 23 of 24 knees with a negative preoperative aspiration, the intraoperative cultures showed no growth on solid media. In 1 knee with a preoperative aspiration that had negative results, a single intraoperative culture grew Staphylococcus epidermidis. However, the presenting symptoms, examination, preoperative radiographs, and intraoperative evaluation were consistent with aseptic loosening of a cemented total knee arthroplasty. Thus, the preoperative aspiration of the prosthetic knee joint had a sensitivity of 100%, specificity of 100%, and accuracy of 100%. The Westergren erythrocyte sedimentation rate, peripheral leukocyte count, and presenting symptoms correlated poorly with infection. Radiographs were also not helpful in the diagnosis of infection, with loosening of components, periostitis, focal osteolysis, and radiolucent lines frequently seen in infected and noninfected knees. Preoperative aspiration of the knee is the most helpful study for the diagnosis or exclusion of infection in a prosthetic knee joint.

Experimental freeze-preservation of chondrocytes.

Preservation of articular cartilage chondrocytes is currently being investigated in conjunction with storage and transplantation of osteochondral allografts. Studies on isolated chondrocytes have suggested that viability and function may be retained following freeze-preservation. Up to 90% of frozen isolated cells will survive, and these cells are capable of producing proteoglycans in culture. Results of freezing chondrocytes in a matrix have not been as successful, with viability ranging from 0% to 50%. Inconsistent results are thought to be due to the matrix and associated problems such as poor penetration of the cryopreservative, an unequal rate of cooling, and a high water content. Studies are in progress in an attempt to produce a satisfactory method of freeze-preservation that will promote normal functioning of chondrocytes after transplantation in an articular cartilage matrix.